1. Field of the invention
The invention generally relates to material or article handling. More specifically, the invention relates to a static receptacle such as a grain storage bin and to non-gravity discharging means for use in such a receptacle. The discharging means may be a discharge assistant of the compound motion type, where the compound motion assistant is displaceable within the receptacle. The invention is specifically directed to improved apparatus for removing grain from a grain storage bin by a sweep auger assembly. The invention is a portable deflector shield that supplements the conventional structure of a sweep auger assembly and directs accumulated grain to the working side of the auger blade rather than allowing such grain to avalanche over the sweep auger assembly.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98
After harvest, grain is stored in a grain storage bin or silo. When the grain is being removed, such as for shipment, a large amount of grain will not discharge from the storage bin under the normal discharge scheme that relies on gravity and a central takeout pit. A sweep auger frequently is used to remove this residual grain. It is notoriously well known that during removal of residual grain, sweep augers suffer from grain avalanche, which is a cascade of grain that passes over the top of an operating sweep auger, falling on the nonworking side where the sweep auger cannot remove this avalanched grain. Teams of workers follow a sweep auger with the intense job of shoveling the avalanched grain back to the working side of the auger. This problem is essentially universal with all known sweep auger designs. The present invention is the first known device that allows workers to correct the problem of avalanching grain by temporarily modifying the configuration of substantially any sweep auger, on the job site.
As background, a grain storage bin typically is cylindrical in shape or at least is circular at floor level. A sweep auger assembly is the standard automated device used for mechanically moving grain from peripheral areas of a storage bin to a central sump. Varieties of sweep augur assembly include both permanent augers that remain installed in a grain bin and portable augers that are brought into a grain bin for temporary use, when needed. U.S. Pat. No. 7,004,305 to Schaefer shows a sweep auger assembly that is formed of multiple small components that can be brought into a grain bin that suffers from limited access and then are assembled inside the bin. Sweep augers operate similarly to one another, although they differ in structure according to type. A permanent sweep auger is exactly sized to fit the bin, while a portable sweep auger is sold in limited, preselected sizes, often multiples of three or five feet. Grain storage bins likewise tend to have an inner radius that is a multiple of three feet, such that a portable sweep auger is likely to be available to fit closely into a grain storage bin.
The primary element of a sweep auger assembly is the auger blade that is approximately equal in length to a radius of the bin or of the area to be cleared. One end of the auger blade, referred to as the inner end, is located centrally in the bin or area to be cleared, near a central sump for discharging grain. The opposite or peripheral end of the auger blade, which will be referred to as the outer end, is located near the cylindrical wall of a cylindrical bin or otherwise at the periphery of an area to be cleared. The auger blade is disposed for rotation on a longitudinal axis of blade rotation that extends between these inner and outer ends, approximately tracking a sweeping or pivoting radius of the bin or area to be cleared. The inner end of the auger is joined near the sump to a central pivot, while the outer end carries a wheel or other drive device that carries the outer end around a circular path at the area periphery or cylindrical wall of the bin. The wheel or other drive device is driven in a preestablished direction that will be referred to as the forward direction. Thus, a drive motor and suitable transmission, coupling, or gearing enable the auger blade to rotate as the auger sweeps forward around the bin from the central pivot point. The auger blade rotates on the longitudinal axis in a rotational direction suitable to impel the grain toward the central sump as the auger moves forward around its circular path.
An auger with a substantially bare auger blade would operate with poor efficiency because grain would fall out the back side of the forward advancing sweep auger. Various types of auger pumps are known, where an auger operates inside a tube that keeps a payload largely within the spiral voids of the auger blade. Sweep augers emulate the pump art to the extent possible, by employing a containment plate over the back side of the auger blade. The back of the sweep auger blade is defined as the trailing face of the blade as the auger moves in the preestablished forward direction. As derived from the pump art, the containment plate is configured as an arc or elongated trough that parallels the rear side of the auger blade and extends for the length of the auger blade. One the auger blade has picked up grain, the containment plate helps to keep the grain in the spiral voids of the auger blade. Because the sweep auger also advances in a forward direction, the containment plate further prevents the auger from leaving the grain behind, as otherwise grain could simply fall out of the auger blade's rear side. However, a containment plate does not solve the problem of grain avalanche.
The containment plate may include a scraper at its bottom edge to help pickup grain and lift it into the auger blade. U.S. Pat. No. 5,511,925 to Sukup shows an adjustable scraper at the bottom of a containment plate. A containment plate is spaced from the rear of an auger blade by a small distance such as an inch to provide clearance and to provide capacity for holding grain. The containment plate can be a part of a frame assembly including end support frames and brackets that carry the auger blade. End support brackets of the frame assembly support the main shaft of the auger blade in bearings.
An auger blade and a containment plate are longitudinally elongated and might sag due to length. A stiffening member or torsion tube is commonly installed between the inner and outer end frame members and is connected to the containment plate to resist sag. U.S. Pat. No. 4,008,816 to Harrison shows a stiffening tube, which Harrison refers to as a torsion arm or torsion tube, joined between the end support brackets, supporting and stiffening the containment plate through clamps between the containment plate and torsion tube at various positions along the torsion tube.
A motor provides power to rotate the auger blade. The same motor or a second motor drives the wheel on the outer end of the auger assembly for advancing the outer end around the bin or area to be cleared. U.S. Pat. No. 4,063,654 to Shivvers shows a sweep auger rotated on a main shaft by a remote drive motor, supported on a wheel at the outer end of the main shaft, and advanced by a ratchet mechanism connected at the outer end of the main shaft and operating in a peripheral, circular track.
The rotational speed of the auger blade typically is greater than the rotational rate of the wheel. A gearbox, transmission, or the like can be used to direct power from the appropriate motor to the auger blade and wheel to establish a wheel speed suitable for advancing the auger, where the wheel speed is suitable for a speed of auger blade rotation. Where a single motor is used to drive both the auger blade and the wheel, a gear reducer controls the wheel speed so that the single motor can drive both the wheel and the auger blade at approximately suitable speeds for transporting grain. However, this ratio is not correct to prevent avalanching in all conditions, due to many variables beyond the control of the auger manufacturer. These include ambient conditions within the bin, characteristics of the particular crop being conveyed, grain depth and distribution pattern, and operating capacity of the auger as compared to size of the bin.
A purpose of initial storage is to reduce the moisture content of grain. To achieve this, the grain bin may be equipped with a perforated floor and powerful fans beneath the floor blowing air into the bin from the bottom. The grain at the bottom of the bin dries first and is removed to another storage location so that grain from higher in the bin can drop to the bottom for further drying. A permanent sweep auger at floor level can be buried under grain when the bin is filled and later used to remove the bottom grain by moving it from all lateral portions of a bin to a central well or sump. Other augers in the sump feed an unloading chute such that grain can be discharged to a waiting truck or conveyor system that is positioned below the unloading chute to receive the grain. Similar equipment can unload an entire storage bin when the crop is to be shipped.
A sweep auger adapted to function while buried under a load of grain must operate under extreme preload. A motor that powers a permanent auger may be located below the floor or outside the bin, where the motor powers the auger through an intermediate coupling. Through a transmission or multiple coupling, the same motor may power additional augers or conveyors in the bin, such as an auger in the sump or unloading chute. A problem with buried augers is that the transmission or couplings may fail, especially if the sweep auger is overly preloaded by dense grain. To reduce the preload problem, an auger designed to operate when buried in grain has a containment plate that extends over the top of the auger blade, forming a substantially horizontal top cover that shields the auger blade from overhead grain. A containment plate that is a top cover does not solve the problem of avalanching. In fact, it contributes to avalanching by deflecting grain from falling into the blade, causing the deflected grain to pass behind the operating auger. U.S. Pat. No. 4,063,654 to Shivvers shows a sweep auger with a top plate over the auger blade, restricting overhead grain intake capacity.
Access limiting top cover and front shields are used in other situations where a sweep auger should not feed too much grain to a downstream location, such as where a downstream auger might become blocked. The Shivvers sweep auger feeds a second, unloading auger and limits payload to prevent blocking. U.S. Pat. No. 5,511,925 to Muth shows both a top plate and a moveable front shield that partially covers the front of the sweep auger blade, greatly restricting the available intake opening. The Muth auger appears to serve a purpose similar to Shivvers, where a permanent auger at the bottom of a grain storage bin is designed to remove bottom layers of grain in a measured process. In addition, the Muth arrangement is directed to a sweep auger feeding a second, vertical lift auger of lower capacity, creating a danger of blocking if the sweep auger delivers grain too quickly to the second auger. Grain augers having top covers and front shields as described in Shivvers and Muth are generally not suitable for use with the present invention.
As described, above, the crop in a grain bin can be unloaded by gravity through the central sump. However, when the stored grain reaches an angle of repose, it will cease to grain by gravity, alone. At this stage of unloading, mechanical assistance is needed to move the remaining grain to the sump. A sweep auger provides the necessary assistance. A portable sweep auger tends to be self-contained, having an auger blade, containment plate, motor, pivot receptor at the inner end, and wheel or other advancement device at the outer end. In addition, a portable sweep auger has a substantially open top, as contrasted with an auger that employs a top cover.
A portable sweep auger is brought into the grain storage bin to remove the residual grain. A portable auger operates at the top of the residual grain and moves grain for the top of the stored load to feed the sump or takeout pit. A grain storage bin provides a fixed central pivot to which the inner end of a portable sweep auger can be pivotally attached. Moving grain to market takes place at a busy time in the agricultural community. A crew of follow-up workers accompanies a portable sweep auger to each storage bin. The inner end of the portable auger is placed on the central pivot, and the auger is operated to clear the storage bin in a single sweep. Constraints of both time and efficiency of operation limit the use of a portable sweep auger to a single sweep. In terms of time, follow-up crews are too busy to wait for such an auger to sweep a bin twice. In terms of efficiency, once the auger has completed a single sweep around the bin, too little grain remains in the bin for the auger to pick up a sufficient load for an efficient second revolution. Nevertheless, the avalanched grain is a large amount in terms of bushels. Thus, follow-up workers equipped with grain shovels have faced the difficult, intense task of follow the auger and restoring avalanched grain to the working side of the auger, all within a single sweep. When the auger is finished with one sweep of a storage bin, the follow-up crew must rapidly remove the auger and advance to the next bin. Any grain that is not swept to the sump is lost.
Grain avalanche over the auger is a major problem with portable sweep augers. As the term implies, grain avalanche is a massive flow of grain over the advancing sweep auger, overrunning the trailing containment plate. Avalanche may occur due to radial fling, due to horizontal overrun, or due to some combination of these and other operating conditions, including the irregular depth and distribution of residual grain in the storage bin. A contributing factor may be imbalance between the rate of grain intake and the rate of auger blade operation. This condition can arise at any time, but especially when the auger digs into irregular masses of stored grain. One of the major tasks of the follow-up work crew is to try to recover the avalanched grain within a single sweep of the bin.
Accordingly, it would be desirable to have a means by which a follow-up work crew could temporarily modify a sweep auger to substantially eliminate grain avalanche. With the exception of sweep augers that are extensively shielded from receiving grain, as by top covers and front shields, a suitable temporary modification can increase auger efficiency sufficiently to solve the avalanche problem. Such a temporary modification may be made permanent. As is evident, the modification is desirable, at least during removal of residual grain, because it increases the operational payload of a sweep auger to handle the grain that otherwise would avalanche over the auger.
It would be further desirable for such a temporary modification to be made so quickly and easily that it does not substantially delay the progress of work. The modification should be made without requiring tools, as tools are easily lost in a grain bin. The modification should be made in a matter of minutes, both for installation and removal, so that the overall installation and removal of the sweep auger is not slowed to a significant extent.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the method and apparatus of this invention may comprise the following.